Methods for restoring metallocene solids exposed to air

ABSTRACT

Methods for treating solid metallocene compounds that are exposed to air are disclosed. These methods include a step of contacting the exposed solid metallocene compound with a purging gas stream containing an inert gas, and optionally, subjecting the exposed solid metallocene compound to a sub-atmospheric pressure.

BACKGROUND OF THE INVENTION

Metallocene compounds, whether in solid form or in solution, aretypically stored in an inert gas atmosphere to prevent degradation andloss of catalytic activity. The conventional method to recovermetallocene solids that are exposed to air (e.g., oxygen and moisture)is recrystallization, but recrystallization is a specialized andtime-consuming process, and is not practical in a production ormanufacturing environment. It would be beneficial to have an improvedmethod for recovering metallocene solids that are exposed to air, whichdoes not involve recrystallization. Accordingly, it is to these andother ends that the present disclosure is directed.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

Methods for treating an exposed solid metallocene compound are disclosedand described herein. One such method for treating an exposed solidmetallocene compound can comprise (or consist essentially of, or consistof) contacting the exposed solid metallocene compound with a purging gasstream that comprises (or consists essentially of, or consists of) aninert gas, to form a treated solid metallocene compound.

Another method for treating an exposed solid metallocene compound isprovided herein, and this method can comprise (or consist essentiallyof, or consist of), in any order, contacting the exposed solidmetallocene compound with a purging gas stream that comprises (orconsists essentially of, or consists of) an inert gas, and subjectingthe exposed solid metallocene compound to a sub-atmospheric pressure, toform a treated solid metallocene compound.

Beneficially, these methods can result in treated solid metallocenecompounds that have comparable color, moisture level, long-termstability, and catalyst activity to that of fresh, unexposed,metallocene compounds that have been stored under nitrogen.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects may bedirected to various feature combinations and sub-combinations describedin the detailed description.

Definitions

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997), can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Herein, features of the subject matter are described such that, withinparticular aspects, a combination of different features can beenvisioned. For each and every aspect and each and every featuredisclosed herein, all combinations that do not detrimentally affect thedesigns, compositions, processes, or methods described herein arecontemplated with or without explicit description of the particularcombination. Additionally, unless explicitly recited otherwise, anyaspect or feature disclosed herein can be combined to describe inventivedesigns, compositions, processes, or methods consistent with the presentdisclosure.

While compositions and methods are described herein in terms of“comprising” various components or steps, the compositions and methodscan also “consist essentially of” or “consist of” the various componentsor steps, unless stated otherwise. For example, a catalyst compositionconsistent with aspects of the present invention can comprise;alternatively, can consist essentially of; or alternatively, can consistof; a treated solid metallocene compound, an activator, and aco-catalyst.

The terms “a,” “an,” “the,” etc., are intended to include pluralalternatives, e.g., at least one, unless otherwise specified. Forinstance, the disclosure of “an activator-support” or “a metallocenecompound” is meant to encompass one, or mixtures or combinations of morethan one, activator-support or metallocene compound, respectively,unless otherwise specified.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements can be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, alkaline earthmetals for Group 2 elements, transition metals for Group 3-12 elements,and halogens or halides for Group 17 elements.

For any particular compound or group disclosed herein, any name orstructure (general or specific) presented is intended to encompass allconformational isomers, regioisomers, stereoisomers, and mixturesthereof that can arise from a particular set of substituents, unlessotherwise specified. The name or structure (general or specific) alsoencompasses all enantiomers, diastereomers, and other optical isomers(if there are any) whether in enantiomeric or racemic forms, as well asmixtures of stereoisomers, as would be recognized by a skilled artisan,unless otherwise specified. A general reference to pentane, for example,includes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane; and ageneral reference to a butyl group includes a n-butyl group, a sec-butylgroup, an iso-butyl group, and a t-butyl group.

Unless otherwise specified, the term “substituted” when used to describea group, for example, when referring to a substituted analog of aparticular group, is intended to describe any non-hydrogen moiety thatformally replaces a hydrogen in that group, and is intended to benon-limiting. Also, unless otherwise specified, a group or groups canalso be referred to herein as “unsubstituted” or by equivalent termssuch as “non-substituted,” which refers to the original group in which anon-hydrogen moiety does not replace a hydrogen within that group.Moreover, unless otherwise specified, “substituted” is intended to benon-limiting and include inorganic substituents or organic substituentsas understood by one of ordinary skill in the art.

The term “hydrocarbon” whenever used in this specification and claimsrefers to a compound containing only carbon and hydrogen, whethersaturated or unsaturated. Other identifiers can be utilized to indicatethe presence of particular groups in the hydrocarbon (e.g., halogenatedhydrocarbon indicates the presence of one or more halogen atomsreplacing an equivalent number of hydrogen atoms in the hydrocarbon).The term “hydrocarbyl group” is used herein in accordance with thedefinition specified by IUPAC: a univalent group formed by removing ahydrogen atom from a hydrocarbon (that is, a group containing onlycarbon and hydrogen). Non-limiting examples of hydrocarbyl groupsinclude alkyl, alkenyl, aryl, and aralkyl groups, amongst other groups.

The term “polymer” is used herein generically to include olefinhomopolymers, copolymers, terpolymers, and so forth, as well as alloysand blends thereof. The term “polymer” also includes all possiblegeometrical configurations, unless stated otherwise, and suchconfigurations can include isotactic, syndiotactic, and randomsymmetries. The term “polymer” also includes impact, block, graft,random, and alternating copolymers. A copolymer can be derived from anolefin monomer and one olefin comonomer, while a terpolymer can bederived from an olefin monomer and two olefin comonomers. Accordingly,“polymer” encompasses copolymers, terpolymers, etc., derived from anyolefin monomer and comonomer(s) disclosed herein. Similarly, an ethylenepolymer would include ethylene homopolymers, ethylene copolymers,ethylene terpolymers, and the like. As an example, an olefin copolymer,such as an ethylene copolymer, can be derived from ethylene and acomonomer, such as 1-butene, 1-hexene, or 1-octene. If the monomer andcomonomer were ethylene and 1-hexene, respectively, the resultingpolymer can be categorized an as ethylene/1-hexene copolymer. The term“polymer” also is meant to include all molecular weight polymers, and isinclusive of lower molecular weight polymers or oligomers. The term“polymer” as used herein is intended to encompass oligomers derived fromany olefin monomer disclosed herein (as well from an olefin monomer andone olefin comonomer, an olefin monomer and two olefin comonomers, andso forth).

In like manner, the scope of the term “polymerization” includeshomopolymerization, copolymerization, and terpolymerization, as well asprocesses that might also be referred to as oligomerization processes.Therefore, a copolymerization process can involve contacting an olefinmonomer (e.g., ethylene) and an olefin comonomer (e.g., 1-hexene) toproduce an olefin copolymer.

The term “co-catalyst” is used generally herein to refer to compoundssuch as aluminoxane compounds, organoboron or organoborate compounds,ionizing ionic compounds, organoaluminum compounds, organozinccompounds, organomagnesium compounds, organolithium compounds, and thelike, that can constitute one component of a catalyst composition, whenused, for example, in addition to an activator-support. The term“co-catalyst” is used regardless of the actual function of the compoundor any chemical mechanism by which the compound may operate.

The term “activator-support” is used herein to indicate a solid,inorganic oxide of relatively high porosity, which can exhibit Lewisacidic or Brønsted acidic behavior, and which has been treated with anelectron-withdrawing component, typically an anion, and which iscalcined. The electron-withdrawing component is typically anelectron-withdrawing anion source compound. Thus, the activator-supportcan comprise a calcined contact product of at least one solid oxide withat least one electron-withdrawing anion source compound. The terms“support” and “activator-support” are not used to imply these componentsare inert, and such components should not be construed as an inertcomponent of the catalyst composition. The term “activator,” as usedherein, refers generally to a substance that is capable of converting ametallocene component into a catalyst that can polymerize olefins, orconverting a contact product of a metallocene component and a componentthat provides an activatable ligand (e.g., an alkyl, a hydride) to themetallocene, when the metallocene compound does not already comprisesuch a ligand, into a catalyst that can polymerize olefins. This term isused regardless of the actual activating mechanism. Illustrativeactivators include activator-supports, aluminoxanes, organoboron ororganoborate compounds, ionizing ionic compounds, and the like.Aluminoxanes, organoboron or organoborate compounds, and ionizing ioniccompounds generally are referred to as activators if used in a catalystcomposition in which an activator-support is not present. If thecatalyst composition contains an activator-support, then thealuminoxane, organoboron or organoborate, and ionizing ionic materialsare typically referred to as co-catalysts.

The term “metallocene” as used herein describes compounds comprising atleast one η³ to η⁵-cycloalkadienyl-type moiety, wherein η³ toη⁵-cycloalkadienyl moieties include cyclopentadienyl ligands, indenylligands, fluorenyl ligands, and the like, including partially saturatedor substituted derivatives or analogs of any of these. Possiblesubstituents on these ligands can include H, therefore this inventioncomprises ligands such as tetrahydroindenyl, tetrahydrofluorenyl,octahydrofluorenyl, partially saturated indenyl, partially saturatedfluorenyl, substituted partially saturated indenyl, substitutedpartially saturated fluorenyl, and the like. All cyclopentadienyl,indenyl, and fluorenyl groups are meant to encompass substituted orunsubstituted cyclopentadienyl, indenyl, and fluorenyl groups, unlessstated otherwise. In some contexts, the metallocene can be referred tosimply as the “catalyst,” in much the same way the term “co-catalyst”can be used herein to refer to, for example, an organoaluminum compound.

In this disclosure, an “exposed” solid metallocene compound refers to asolid metallocene compound that has been exposed to air (oxygen,moisture), and the exposed solid metallocene compound may be partiallyhydrolyzed and/or may exhibit a color change (although not required), ascompared to a “fresh” solid metallocene compound. The “fresh” solidmetallocene compound is the reference or standard metallocene compound,unexposed to air, and generally stored under an inert gas such asnitrogen. A “treated” solid metallocene compound refers to the “exposed”solid metallocene compound after it has been treated in accordance withthe methods disclosed herein, and also can be referred to as beingrecovered or restored.

The terms “catalyst composition,” “catalyst mixture,” “catalyst system,”and the like, do not depend upon the actual product or compositionresulting from the contact or reaction of the initial components of thedisclosed or claimed catalyst composition/mixture/system, the nature ofthe active catalytic site, or the fate of the co-catalyst, themetallocene compound, or the activator (e.g., activator-support), aftercombining these components. Therefore, the terms “catalyst composition,”“catalyst mixture,” “catalyst system,” and the like, encompass theinitial starting components of the composition, as well as whateverproduct(s) may result from contacting these initial starting components,and this is inclusive of both heterogeneous and homogenous catalystsystems or compositions. The terms “catalyst composition,” “catalystmixture,” “catalyst system,” and the like, can be used interchangeablythroughout this disclosure.

The terms “contact product,” “contacting,” and the like, are used hereinto describe methods and compositions wherein the components are combinedor contacted together in any order, in any manner, and for any length oftime, unless otherwise specified. For example, the components can becontacted by blending or mixing. Further, unless otherwise specified,the contacting of any component can occur in the presence or absence ofany other component of the methods and compositions described herein.Combining additional materials or components can be done by any suitablemethod. These terms encompass materials which can be blended, mixed,slurried, dissolved, reacted, treated, or otherwise contacted in someother manner.

Although any methods and materials similar or equivalent to thosedescribed herein can be used in the practice or testing of theinvention, the typical methods and materials are herein described.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention.

Several types of ranges are disclosed herein. When a range of any typeis disclosed or claimed herein, the intent is to disclose or claimindividually each possible number that such a range could reasonablyencompass, including end points of the range as well as any sub-rangesand combinations of sub-ranges encompassed therein, unless otherwisespecified. As a representative example, the present disclosure setsforth that the purging step can be performed at a purging temperature ina range from about 10° C. to about 75° C., in certain aspects. By adisclosure that the purging temperature can be in a range from about 10°C. to about 75° C., the intent is to recite that the purging temperaturecan be any temperature within the range and, for example, can be equalto about 10° C., about 20° C., about 30° C., about 40° C., about 50° C.,about 60° C., about 70° C., or about 75° C. Additionally, the purgingtemperature can be within any range from about 10° C. to about 75° C.(for example, the temperature can be in a range from about 15° C. toabout 50° C.), and this also includes any combination of ranges betweenabout 10° C. to about 75° C. Likewise, all other ranges disclosed hereinshould be interpreted in a manner similar to this example.

The term “about” means that amounts, sizes, formulations, parameters,and other quantities and characteristics are not and need not be exact,but may be approximate including being larger or smaller, as desired,reflecting tolerances, conversion factors, rounding off, measurementerrors, and the like, and other factors known to those of skill in theart. In general, an amount, size, formulation, parameter or otherquantity or characteristic is “about” or “approximate” whether or notexpressly stated to be such. The term “about” also encompasses amountsthat differ due to different equilibrium conditions for a compositionresulting from a particular initial mixture. Whether or not modified bythe term “about,” the claims include equivalents to the quantities. Theterm “about” can mean within 10% of the reported numerical value, andoften within 5% of the reported numerical value.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein are methods for treating solid metallocene compoundsthat have been exposed to air (e.g., oxygen and moisture), withoututilizing a recrystallization process. Beneficially, catalyst solutionsprepared from the treated solid metallocene compounds of this inventiontypically have comparable color, moisture level, long-term stability,and/or catalyst activity to that of solutions prepared from fresh andunexposed samples of the respective metallocene compounds that have beenstored under nitrogen. Other potential benefits of the methods disclosedherein are readily apparent to those of skill in the art in view of thisdisclosure.

Methods for Treating Exposed Solid Metallocene Compounds

Various methods for treating an exposed solid metallocene compound aredisclosed and described herein. A first method for treating an exposedsolid metallocene compound can comprise (or consist essentially of, orconsist of) contacting the exposed solid metallocene compound with apurging gas stream comprising (or consisting essentially of, orconsisting of) an inert gas to form a treated solid metallocenecompound.

Generally, the features of the first method (e.g., the exposed solidmetallocene compound, the treated solid metallocene compound, theconditions under which the exposed solid metallocene compound iscontacted with the purging gas stream, and the inert gas, among others)are independently described herein, and these features may be combinedin any combination to further describe this first method. Moreover,other process steps may be conducted before, during, and/or after thestep listed in the first method, unless stated otherwise. Additionally,treated solid metallocene compounds prepared in accordance with thisfirst method are within the scope of this disclosure and are encompassedherein.

The step in the first method in which the exposed solid metallocenecompound is contacted with a purging gas stream often is referred toherein as a purging step. Additionally, any compositional attributes ofthe purging gas stream are meant to refer to the incoming purging gassteam, prior to contacting the exposed solid metallocene compound,unless expressly stated otherwise. As one of skill in the art wouldreadily recognize, the outgoing purging gas stream, after contactingexposed solid metallocene compound, can vary significantly incomposition from the incoming purging gas stream.

The purging step generally can comprise contacting the exposed solidmetallocene compound with a purging gas stream comprising (or consistingessentially of, or consisting of) an inert gas. The inert gas can behelium, neon, argon, or nitrogen, or a mixture thereof; alternatively,helium; alternatively, neon; alternatively, argon; or alternatively,nitrogen.

Additionally, in some aspects, the purging gas stream can besubstantially free of oxygen-containing compounds (e.g., O₂), i.e., thepurging gas stream can contain less than 50 ppmw (ppm by weight) ofoxygen-containing compounds. Therefore, it is contemplated that theamount of oxygen-containing compounds in the purging gas stream can beless than or equal to 25 ppmw, less than or equal to 10 ppmw, less thanor equal to 5 ppmw, less than or equal to 3 ppmw, or less than or equalto 1 ppmw, in certain aspects. While not wishing to be bound by thefollowing theory, it can be beneficial to have substantially no oxygenadded during the purging step to treat the exposed solid metallocenecompound. In particular aspects of this invention, therefore, it can bebeneficial for the purging gas stream to contain less than or equal to15 ppmw of oxygen-containing compounds; alternatively, less than orequal to 10 ppmw of oxygen-containing compounds; alternatively, lessthan or equal to 5 ppmw of oxygen-containing compounds; oralternatively, less than or equal to 1 ppmw of oxygen-containingcompounds.

Moreover, although not required, the purging gas stream can besubstantially free of water (moisture), i.e., the purging gas stream cancontain less than 50 ppmw (ppm by weight) of water. As above, it iscontemplated that the amount of water in the purging gas stream can beless than or equal to 25 ppmw, less than or equal to 10 ppmw, less thanor equal to 5 ppmw, less than or equal to 3 ppmw, or less than or equalto 1 ppmw, in certain aspects. While not wishing to be bound by thefollowing theory, it can be beneficial to have substantially water ormoisture added during the purging step to treat the exposed solidmetallocene compound. In particular aspects of this invention,therefore, it can be beneficial for the purging gas stream to containless than or equal to 15 ppmw of water; alternatively, less than orequal to 10 ppmw of water; alternatively, less than or equal to 5 ppmwof water; or alternatively, less than or equal to 1 ppmw of water.

The purging step can be conducted at a variety of temperatures and timeperiods. For instance, the purging step can be conducted at a purgingtemperature in a range from about 0° C. to about 100° C.; alternatively,from about 0° C. to about 75° C.; alternatively, from about 10° C. toabout 75° C.; alternatively, from about 20° C. to about 60° C.;alternatively, from about 20° C. to about 50° C.; alternatively, fromabout 15° C. to about 50° C.; or alternatively, from about 20° C. toabout 40° C. In these and other aspects, these temperature ranges alsoare meant to encompass circumstances where the purging step is conductedat a series of different temperatures, instead of at a single fixedtemperature, falling within the respective ranges. Further, while notwishing to be bound by the following theory, it is believed that thestability of the metallocene compound can be impacted by exposure toelevated temperatures, and therefore, excessive temperatures should beavoided, or if experienced, only for short durations.

The duration of the purging step is not limited to any particular periodof time. Typically, the purging step can be conducted in a time periodranging from as little as 15-30 minutes to as long as 48-72 hours (ormore), but more typically, the purging step can be conducted in a timeperiod ranging from about 15 min to about 72 hours, such as, forexample, from about 30 min to about 48 hours, from about 1 hour to about24 hours, from about 1 hour to about 12 hours, from about 2 hours toabout 8 hours, from about 30 min to about 3 hours, from about 15 min toabout 6 hours, or from about 1 hour to about 6 hours.

Alternatively, the purging step can be conducted for a time periodsufficient to reach at least 80% of the catalyst activity of a freshsolid metallocene compound, after 24 hours in a toluene solution, underthe same polymerization conditions. That is, the purging step can beperformed on the exposed solid metallocene compound for a time periodsufficient for the catalyst activity of the treated solid metallocenecompound to be at least 80% of the catalyst activity of a fresh solidmetallocene compound. The catalyst activities for the treated solidmetallocene compound and the fresh solid metallocene compound are testedon a solution containing 1 mg of metallocene in 1 mL of toluene, afterstorage under nitrogen for 24 hours at 25° C. The same polymerizationconditions refer to slurry polymerization conditions, using isobutane asa diluent, and with a polymerization temperature of 90° C. and a reactorpressure of 390 psig. Moreover, all components used to prepare thecatalyst systems are held constant (e.g., same amount of metallocenecompound, same amount/type of organoaluminum (e.g., TIBA), sameamount/type of activator-support (e.g., fluorided silica-coated alumina)and all polymerization conditions are held constant (e.g., samepolymerization temperature, same pressure). Hence, the only differenceis the use of the fresh solid metallocene compound instead of thetreated solid metallocene compound.

In further aspects, the purging step can be conducted for a time periodsufficient to reach at least 85%, at least 90%, or at least 95%, of thecatalyst activity of the fresh solid metallocene compound, after 24hours in a toluene solution, under the same polymerization conditions.

In another aspect, the purging step can be conducted for a time periodsufficient to maintain the color of a 1 mg/mL solution of the treatedsolid metallocene compound for at least 24 hours at 25° C. That is, thepurging step can be performed on the exposed solid metallocene compoundfor a time period sufficient for the treated solid metallocene compoundto maintain its color (i.e., visually, the same color as that of thefresh solid metallocene compound) in a 1 mg/mL solution of the treatedsolid metallocene compound for at least 24 hours at 25° C. (stored undernitrogen). The solvent can be any suitable solvent for the metallocenecompound, but often, toluene can be used.

In further aspects, the purging step can be conducted for a time periodsufficient to maintain the color of a 1 mg/mL solution of the treatedsolid metallocene compound for 24 hours, for 30 hours, for 36 hours, orfor 48 hours, at 25° C.

The purging step can be performed in any suitable vessel or container,and any method known to a skilled artisan for contacting the exposedsolid metallocene compound with the purging gas stream can be utilized.In one aspect, for instance, the exposed solid metallocene compound canbe placed in a vessel and the purging gas can be introduced into thevessel to contact the solid material. In another aspect, the exposedsolid metallocene compound can be placed in a vessel in a fixed bedarrangement, and the purging gas can be flowed through the fixed bed ofthe solid material. In yet another aspect, the exposed solid metallocenecompound can be placed in a vessel, and the solid material can befluidized with the purging gas stream.

A second method for treating an exposed solid metallocene compound cancomprise (or consist essentially of, or consist of), in any order:

contacting the exposed solid metallocene compound with a purging gasstream comprising (or consisting essentially of, or consisting of) aninert gas; and

subjecting the exposed solid metallocene compound to a sub-atmosphericpressure; to form a treated solid metallocene compound.

Generally, the features of the second method (e.g., the exposed solidmetallocene compound, the treated solid metallocene compound, theconditions under which the exposed solid metallocene compound iscontacted with the purging gas stream, the inert gas, and the conditionsunder which the exposed solid metallocene compound is exposed tosub-atmospheric pressure, among others) are independently describedherein, and these features may be combined in any combination to furtherdescribe this second method. Moreover, other process steps may beconducted before, during, and/or after the steps listed in the secondmethod, unless stated otherwise. Additionally, treated solid metallocenecompounds prepared in accordance with this second method are within thescope of this disclosure and are encompassed herein.

Any characteristics or features of the purging step in this secondmethod for treating an exposed solid metallocene compound can be thesame as those described herein for the purging step in the first methodfor treating an exposed solid metallocene compound. Additionally, thestep in the second method in which the exposed solid metallocenecompound is subjected to a sub-atmospheric pressure often is referred toherein as a vacuum step.

The subjecting step (or vacuum step) in the second method for treatingan exposed solid metallocene compound can comprise subjecting theexposed solid metallocene compound to any suitable sub-atmosphericpressure. For instance, and not limited thereto, the pressure can beless than 100 torr, less than 50 torr, less than 10 torr, or less than 1torr. Illustrative pressure ranges can include, for example, from about100 to about 0.01 torr, from about 10 to about 0.1 torr, or from about 1to about 0.1 torr.

The subjecting step (or vacuum step) can be conducted at a variety oftemperatures and time periods. For instance, the subjecting step can beconducted at a vacuum temperature in a range from about 0° C. to about100° C.; alternatively, from about 0° C. to about 75° C.; alternatively,from about 10° C. to about 75° C.; alternatively, from about 20° C. toabout 60° C.; alternatively, from about 20° C. to about 50° C.;alternatively, from about 15° C. to about 50° C.; or alternatively, fromabout 20° C. to about 40° C. In these and other aspects, thesetemperature ranges also are meant to encompass circumstances where thevacuum step is conducted at a series of different temperatures, insteadof at a single fixed temperature, falling within the respective ranges.Further, while not wishing to be bound by the following theory, it isbelieved that the stability of the metallocene compound can be impactedby exposure to elevated temperatures, and therefore, excessivetemperatures should be avoided, or if experienced, only for shortdurations.

The duration of the subjecting step (or vacuum step) is not limited toany particular period of time, and the duration can vary depending uponthe vacuum temperature and the sub-atmospheric pressure used (e.g., 0.5torr versus 50 torr). Typically, the subjecting step can be conducted ina time period ranging from as little as 15-30 minutes to as long as48-72 hours (or more), but more typically, the subjecting step can beconducted in a time period ranging from about 15 min to about 72 hours,such as, for example, from about 30 min to about 48 hours, from about 1hour to about 24 hours, from about 1 hour to about 12 hours, from about2 hours to about 8 hours, from about 30 min to about 3 hours, from about15 min to about 6 hours, or from about 1 hour to about 6 hours.

The second method can be conducted by performing any number ofcontacting (purging) cycles and any number of subjecting (vacuum)cycles, and these cycles can be performed in any order or sequence.Thus, the method can comprise from 1 to 8, from 1 to 6, from 1 to 4,from 2 to 6, or from 2 to 4, contacting (purging) cycles and from 1 to8, from 1 to 6, from 1 to 4, from 2 to 6, or from 2 to 4, subjecting(vacuum) cycles. Each contacting (purging) cycle and each subjecting(vacuum) cycle, independently, can be performed at any conditiondisclosed herein (e.g., temperature, time, etc.) for the respectivecontacting (purging) step and subjecting (vacuum) step.

As an example, the second method for treating an exposed solidmetallocene compound can comprise a first contacting (purging) cycle, afirst subjecting (vacuum) cycle, a second contacting (purging) cycle, asecond subjecting (vacuum) cycle, and a third contacting (purging)cycle. Each of these cycles can be performed at any temperature,pressure, and time duration disclosed herein.

As another example, the second method for treating an exposed solidmetallocene compound can comprise a first subjecting (vacuum) cycle, afirst contacting (purging) cycle, a second subjecting (vacuum) cycle,and a second contacting (purging) cycle. Each of these cycles can beperformed at any temperature, pressure, and time duration disclosedherein.

The first method for treating an exposed solid metallocene compound andthe second method for treating an exposed solid metallocene compound,independently, can be conducted under conditions sufficient (e.g.,temperature, pressure, time, cycles, etc.) to reach at least 80% of thecatalyst activity of a fresh solid metallocene compound, after 24 hoursin a toluene solution, under the same polymerization conditions. Thatis, the first method for treating an exposed solid metallocene compoundand the second method for treating an exposed solid metallocenecompound, independently, can be conducted such that the catalystactivity of the treated solid metallocene compound can be at least 80%of the catalyst activity of a fresh solid metallocene compound. Thecatalyst activities for the treated solid metallocene compound and thefresh solid metallocene compound are tested on a solution containing 1mg of metallocene in 1 mL of toluene, after storage under nitrogen for24 hours at 25° C. The same polymerization conditions refer to slurrypolymerization conditions, using isobutane as a diluent, and with apolymerization temperature of 90° C. and a reactor pressure of 390 psig.Moreover, all components used to prepare the catalyst systems are heldconstant (e.g., same amount of metallocene compound, same amount/type oforganoaluminum (e.g., TIBA), same amount/type of activator-support(e.g., fluorided silica-coated alumina) and all polymerizationconditions are held constant (e.g., same polymerization temperature,same pressure). Hence, the only difference is the use of the fresh solidmetallocene compound instead of the treated solid metallocene compound.

In further aspects, the first method for treating an exposed solidmetallocene compound and the second method for treating an exposed solidmetallocene compound, independently, can be conducted under conditionssufficient to reach at least 85%, at least 90%, or at least 95%, of thecatalyst activity of the fresh solid metallocene compound, after 24hours in a toluene solution, under the same polymerization conditions.

In another aspect, the first method for treating an exposed solidmetallocene compound and the second method for treating an exposed solidmetallocene compound, independently, can be conducted under conditionssufficient to maintain the color of a 1 mg/mL solution of the treatedsolid metallocene compound for at least 24 hours at 25° C. That is, thefirst method and the second method, independently, can be performed onthe exposed solid metallocene compound under conditions sufficient forthe treated solid metallocene compound to maintain its color (i.e.,visually, the same color as that of the fresh solid metallocenecompound) in a 1 mg/mL solution of the treated solid metallocenecompound for at least 24 hours at 25° C. (stored under nitrogen). Thesolvent can be any suitable solvent for the metallocene compound, butoften, toluene can be used.

In further aspects, the first method for treating an exposed solidmetallocene compound and the second method for treating an exposed solidmetallocene compound, independently, can be conducted under conditionssufficient to maintain the color of a 1 mg/mL solution of the treatedsolid metallocene compound for 24 hours, for 30 hours, for 36 hours, orfor 48 hours, at 25° C.

Consistent with aspects of this invention, both the first method fortreating an exposed solid metallocene compound and the second method fortreating an exposed solid metallocene compound do not require or use arecrystallization step.

The treated solid metallocene compound prepared by the first method andthe second method can be characterized by very low moisture levels, andsuch can be quantified by the moisture level of a solution containingthe treated solid metallocene compound. A 1 mg/mL solution of thetreated solid metallocene compound is prepared at 25° C. under nitrogen.The solvent can be any suitable solvent for the metallocene compound,but often, toluene can be used. The first and second methods disclosedherein can result in a substantially moisture-free treated solidmetallocene compound, characterized by a 1 mg/mL solution of the treatedsolid metallocene compound having a moisture level of less than 15 ppmw(ppm by weight). In some aspects, the moisture level of a 1 mg/mLsolution of the treated solid metallocene can be less than or equal to10 ppmw, less than or equal to 8 ppmw, less than or equal to 4 ppmw,less than or equal to 2 ppmw, or no measurable amount of moisture. Whilenot wishing to be bound by the following theory, it is believed thatlonger-term stability of the metallocene solution can be improved whenthe moisture level of the solution in less than or equal to 5 ppmw, andeven more so, when the moisture level of the solution is less than orequal to 2 ppmw.

Catalyst Compositions

Catalyst compositions containing the treated solid metallocene compoundand processes for producing catalyst compositions using the treatedsolid metallocene compound also are encompassed herein. For instance,one such process to produce a catalyst composition can comprisecontacting, in any order, (a) any treated solid metallocene compounddisclosed herein, (b) any activator disclosed herein, and (c)optionally, any co-catalyst disclosed herein, to produce the catalystcomposition.

In the preparation of the catalyst composition, the treated solidmetallocene compound can be present as a slurry in a diluent in oneaspect of this invention, while in another aspect of this invention, thetreated solid metallocene compound can be present as a metallocenesolution in a suitable solvent.

Generally, catalyst compositions of the present invention comprise atreated solid metallocene compound and an activator. In aspects of theinvention, the activator can comprise an activator-support (e.g., anactivator-support comprising a solid oxide treated with anelectron-withdrawing anion). Activator-supports useful in the presentinvention are disclosed herein. Optionally, such catalyst compositionscan further comprise one or more than one co-catalyst compound orcompounds (suitable co-catalysts, such as organoaluminum compounds, alsoare discussed herein). Thus, a catalyst composition of this inventioncan comprise a treated solid metallocene compound, an activator-support,and an organoaluminum compound. For instance, the activator-support cancomprise (or consist essentially of, or consist of) fluorided alumina,chlorided alumina, bromided alumina, sulfated alumina, fluoridedsilica-alumina, chlorided silica-alumina, bromided silica-alumina,sulfated silica-alumina, fluorided silica-zirconia, chloridedsilica-zirconia, bromided silica-zirconia, sulfated silica-zirconia,fluorided silica-titania, fluorided-chlorided silica-coated alumina,fluorided silica-coated alumina, sulfated silica-coated alumina,phosphated silica-coated alumina, and the like, or combinations thereof;or alternatively, a fluorided solid oxide and/or a sulfated solid oxide.Additionally, the organoaluminum compound can comprise (or consistessentially of, or consist of) trimethylaluminum, triethylaluminum,tri-n-propylaluminum, tri-n-butyl aluminum, triisobutylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride,diethylaluminum ethoxide, diethylaluminum chloride, and the like, orcombinations thereof. Accordingly, a catalyst composition consistentwith aspects of the invention can comprise (or consist essentially of,or consist of) a treated solid metallocene compound; sulfated alumina(or fluorided-chlorided silica-coated alumina, or fluoridedsilica-coated alumina); and triethylaluminum (or triisobutylaluminum).

In another aspect of the present invention, a catalyst composition isprovided which comprises a treated solid metallocene compound, anactivator-support, and an organoaluminum compound, wherein this catalystcomposition is substantially free of aluminoxanes, organoboron ororganoborate compounds, ionizing ionic compounds, and/or other similarmaterials; alternatively, substantially free of aluminoxanes;alternatively, substantially free or organoboron or organoboratecompounds; or alternatively, substantially free of ionizing ioniccompounds. In these aspects, the catalyst composition has catalystactivity, discussed herein, in the absence of these additionalmaterials. For example, a catalyst composition of the present inventioncan consist essentially of a treated solid metallocene compound, anactivator-support, and an organoaluminum compound, wherein no othermaterials are present in the catalyst composition which wouldincrease/decrease the activity of the catalyst composition by more thanabout 10% from the catalyst activity of the catalyst composition in theabsence of said materials.

However, in other aspects of this invention, theseactivators/co-catalysts can be employed. For example, a catalystcomposition comprising a treated solid metallocene compound and anactivator-support can further comprise a co-catalyst. Suitableco-catalysts in this aspect can include, but are not limited to,aluminoxane compounds, organoboron or organoborate compounds, ionizingionic compounds, organoaluminum compounds, organozinc compounds,organomagnesium compounds, organolithium compounds, and the like, or anycombination thereof; or alternatively, organoaluminum compounds,organozinc compounds, organomagnesium compounds, organolithiumcompounds, or any combination thereof. More than one co-catalyst can bepresent in the catalyst composition.

In a different aspect, a catalyst composition is provided which does notrequire an activator-support. Such catalyst composition can comprise atreated solid metallocene compound and an activator, wherein theactivator can comprise an aluminoxane compound (e.g., a supportedaluminoxane), an organoboron or organoborate compound, an ionizing ioniccompound, or combinations thereof; alternatively, an aluminoxanecompound; alternatively, an organoboron or organoborate compound; oralternatively, an ionizing ionic compound.

Metallocene Compounds

As discussed herein, the metallocene compound can be described as anexposed metallocene compound, a treated metallocene compound, or a freshmetallocene compound. Regardless of the nomenclature or terminology, itis believed that any solid metallocene compound that has been exposed toair and/or moisture can benefit from the methods disclosed herein,regardless of its chemical structure.

Accordingly, the metallocene compound can comprise a bridged metallocenecompound and/or an unbridged metallocene compound. The metallocenecompound can comprise, for example, a transition metal (one or more thanone) from Groups 3-8 of the Periodic Table of the Elements. In oneaspect, the metallocene compound can comprise a Group 3 to Group 6transition metal, or a combination of two or more transition metals. Themetallocene compound can comprise chromium, titanium, zirconium,hafnium, vanadium, or a combination thereof, or can comprise titanium,zirconium, hafnium, or a combination thereof, in other aspects. Infurther aspects, the metallocene compound can comprise titanium, orzirconium, or hafnium, either singly or in combination.

In some aspects of this invention, the metallocene compound can comprisea bridged metallocene compound, e.g., with titanium, zirconium, orhafnium, such as a bridged zirconium or hafnium based metallocenecompound with a fluorenyl group, and with no aryl groups on the bridginggroup, or a bridged zirconium or hafnium based metallocene compound witha cyclopentadienyl group and a fluorenyl group, and with no aryl groupson the bridging group. Such bridged metallocenes, in some aspects, cancontain an alkenyl substituent (e.g., a terminal alkenyl) on thebridging group and/or on a cyclopentadienyl-type group (e.g., acyclopentadienyl group or a fluorenyl group). In another aspect, themetallocene compound can comprise a bridged zirconium or hafnium basedmetallocene compound with a fluorenyl group, and an aryl group on thebridging group; alternatively, a bridged zirconium or hafnium basedmetallocene compound with a cyclopentadienyl group and fluorenyl group,and an aryl group on the bridging group; alternatively, a bridgedzirconium based metallocene compound with a fluorenyl group, and an arylgroup on the bridging group; or alternatively, a bridged hafnium basedmetallocene compound with a fluorenyl group, and an aryl group on thebridging group. In these and other aspects, the aryl group on thebridging group can be a phenyl group. Optionally, these bridgedmetallocenes can contain an alkenyl substituent (e.g., a terminalalkenyl) on the bridging group and/or on a cyclopentadienyl-type group.

In some aspects, the metallocene compound can comprise a bridgedzirconium or hafnium based metallocene compound with two indenyl groups(e.g., a bis-indenyl metallocene compound). Hence, the metallocenecompound can comprise a bridged zirconium based metallocene compoundwith two indenyl groups, or alternatively, a bridged hafnium basedmetallocene compound with two indenyl groups. In some aspects, an arylgroup can be present on the bridging group, while in other aspects,there are no aryl groups present on the bridging group. Optionally,these bridged indenyl metallocenes can contain an alkenyl substituent(e.g., a terminal alkenyl) on the bridging group and/or on the indenylgroup (one or both indenyl groups). The bridging atom of the bridginggroup can be, for instance, a carbon atom or a silicon atom;alternatively, the bridge can contain a chain of two carbon atoms, achain of two silicon atoms, and so forth.

Illustrative and non-limiting examples of bridged metallocene compounds(e.g., with zirconium or hafnium) that can be used in methods consistentwith aspects of the present invention are described in U.S. Pat. Nos.7,026,494, 7,041,617, 7,226,886, 7,312,283, 7,517,939, and 7,619,047,the disclosures of which are incorporated herein by reference in theirentirety.

In some aspects of this invention, the metallocene compound can comprisean unbridged metallocene; alternatively, an unbridged zirconium orhafnium based metallocene compound and/or an unbridged zirconium and/orhafnium based dinuclear metallocene compound; alternatively, anunbridged zirconium or hafnium based metallocene compound containing twocyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl andan indenyl group; alternatively, an unbridged zirconium basedmetallocene compound containing two cyclopentadienyl groups, two indenylgroups, or a cyclopentadienyl and an indenyl group. Illustrative andnon-limiting examples of unbridged metallocene compounds (e.g., withzirconium or hafnium) that can be used in methods consistent withaspects of the present invention are described in U.S. Pat. Nos.7,199,073, 7,226,886, 7,312,283, and 7,619,047, the disclosures of whichare incorporated herein by reference in their entirety.

Moreover, the metallocene compound can comprise an unbridged dinuclearmetallocene such as those described in U.S. Pat. Nos. 7,919,639 and8,080,681, the disclosures of which are incorporated herein by referencein their entirety. The metallocene compound can comprise an unbridgedzirconium and/or hafnium based dinuclear metallocene compound. Forexample, the metallocene compound can comprise an unbridged zirconiumbased homodinuclear metallocene compound, or an unbridged hafnium basedhomodinuclear metallocene compound, or an unbridged zirconium and/orhafnium based heterodinuclear metallocene compound (i.e., a dinuclearcompound with two hafniums, or two zirconiums, or one zirconium and onehafnium).

Activator-Supports

The present invention encompasses various catalyst compositionscontaining an activator-support. In one aspect, the activator-supportcan comprise a solid oxide treated with an electron-withdrawing anion.Alternatively, in another aspect, the activator-support can comprise asolid oxide treated with an electron-withdrawing anion, the solid oxidecontaining a Lewis-acidic metal ion. Non-limiting examples of suitableactivator-supports are disclosed in, for instance, U.S. Pat. Nos.7,294,599, 7,601,665, 7,884,163, 8,309,485, 8,623,973, 8,703,886, and9,023,959, which are incorporated herein by reference in their entirety.

The solid oxide can encompass oxide materials such as alumina, “mixedoxides” thereof such as silica-alumina, coatings of one oxide onanother, and combinations and mixtures thereof. The mixed oxides such assilica-alumina can be single or multiple chemical phases with more thanone metal combined with oxygen to form the solid oxide. Examples ofmixed oxides that can be used to form an activator-support, eithersingly or in combination, can include, but are not limited to,silica-alumina, silica-titania, silica-zirconia, alumina-titania,alumina-zirconia, zinc-aluminate, alumina-boria, silica-boria,aluminophosphate-silica, titania-zirconia, and the like. The solid oxideused herein also encompasses oxide materials such as silica-coatedalumina, as described in U.S. Pat. No. 7,884,163 (e.g., Sasol Siral® 28,Sasol Siral® 40, etc.).

Accordingly, in one aspect, the solid oxide can comprise silica,alumina, silica-alumina, silica-coated alumina, aluminum phosphate,aluminophosphate, heteropolytungstate, titania, silica-titania,zirconia, silica-zirconia, magnesia, boria, zinc oxide, any mixed oxidethereof, or any combination thereof. In another aspect, the solid oxidecan comprise alumina, silica-alumina, silica-coated alumina, aluminumphosphate, aluminophosphate, heteropolytungstate, titania,silica-titania, zirconia, silica-zirconia, magnesia, boria, or zincoxide, as well as any mixed oxide thereof, or any mixture thereof. Inanother aspect, the solid oxide can comprise silica, alumina, titania,zirconia, magnesia, boria, zinc oxide, any mixed oxide thereof, or anycombination thereof. In yet another aspect, the solid oxide can comprisesilica-alumina, silica-coated alumina, silica-titania, silica-zirconia,alumina-boria, or any combination thereof. In still another aspect, thesolid oxide can comprise alumina, silica-alumina, silica-coated alumina,or any mixture thereof; alternatively, alumina; alternatively,silica-alumina; or alternatively, silica-coated alumina.

The silica-alumina or silica-coated alumina solid oxide materials whichcan be used can have an silica content from about 5 to about 95% byweight. In one aspect, the silica content of these solid oxides can befrom about 10 to about 80%, or from about 20% to about 70%, silica byweight. In another aspect, such materials can have silica contentsranging from about 15% to about 60%, from about 20% to about 50%, orfrom about 25% to about 45%, silica by weight. The solid oxidescontemplated herein can have any suitable surface area, pore volume, andparticle size, as would be recognized by those of skill in the art.

The electron-withdrawing component used to treat the solid oxide can beany component that increases the Lewis or Brønsted acidity of the solidoxide upon treatment (as compared to the solid oxide that is not treatedwith at least one electron-withdrawing anion). According to one aspect,the electron-withdrawing component can be an electron-withdrawing anionderived from a salt, an acid, or other compound, such as a volatileorganic compound, that serves as a source or precursor for that anion.Examples of electron-withdrawing anions can include, but are not limitedto, sulfate, bisulfate, fluoride, chloride, bromide, iodide,fluorosulfate, fluoroborate, phosphate, fluorophosphate,trifluoroacetate, triflate, fluorozirconate, fluorotitanate,phospho-tungstate, tungstate, molybdate, and the like, includingmixtures and combinations thereof. In addition, other ionic or non-ioniccompounds that serve as sources for these electron-withdrawing anionsalso can be employed. It is contemplated that the electron-withdrawinganion can be, or can comprise, fluoride, chloride, bromide, phosphate,triflate, bisulfate, or sulfate, and the like, or any combinationthereof, in some aspects provided herein. In other aspects, theelectron-withdrawing anion can comprise sulfate, bisulfate, fluoride,chloride, bromide, iodide, fluorosulfate, fluoroborate, phosphate,fluorophosphate, trifluoroacetate, triflate, fluorozirconate,fluorotitanate, and the like, or combinations thereof. Yet, in otheraspects, the electron-withdrawing anion can comprise fluoride and/orsulfate.

The activator-support generally can contain from about 1 to about 25 wt.% of the electron-withdrawing anion, based on the weight of theactivator-support. In particular aspects provided herein, theactivator-support can contain from about 1 to about 20 wt. %, from about2 to about 20 wt. %, from about 3 to about 20 wt. %, from about 2 toabout 15 wt. %, from about 3 to about 15 wt. %, from about 3 to about 12wt. %, or from about 4 to about 10 wt. %, of the electron-withdrawinganion, based on the total weight of the activator-support.

In an aspect, the activator-support can comprise fluorided alumina,chlorided alumina, bromided alumina, sulfated alumina, phosphatedalumina, fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, phosphated silica-alumina,fluorided silica-zirconia, chlorided silica-zirconia, bromidedsilica-zirconia, sulfated silica-zirconia, fluorided silica-titania,fluorided silica-coated alumina, fluorided-chlorided silica-coatedalumina, sulfated silica-coated alumina, phosphated silica-coatedalumina, and the like, as well as any mixture or combination thereof. Inanother aspect, the activator-support employed in the processes andcatalyst systems described herein can be, or can comprise, a fluoridedsolid oxide and/or a sulfated solid oxide and/or a phosphated solidoxide, non-limiting examples of which can include fluorided alumina,sulfated alumina, phosphated alumina, fluorided silica-alumina, sulfatedsilica-alumina, phosphated silica-alumina, fluorided silica-zirconia,fluorided silica-coated alumina, fluorided-chlorided silica-coatedalumina, sulfated silica-coated alumina, phosphated silica-coatedalumina, and the like, as well as combinations thereof. In yet anotheraspect, the activator-support can comprise fluorided alumina;alternatively, chlorided alumina; alternatively, sulfated alumina;alternatively, phosphated alumina; alternatively, fluoridedsilica-alumina; alternatively, sulfated silica-alumina; alternatively,phosphated silica-alumina; alternatively, fluorided silica-zirconia;alternatively, chlorided silica-zirconia; alternatively, sulfatedsilica-coated alumina; alternatively, phosphated silica-coated alumina;alternatively, fluorided-chlorided silica-coated alumina; oralternatively, fluorided silica-coated alumina.

Various processes can be used to form activator-supports useful in thepresent invention. Methods of contacting the solid oxide with theelectron-withdrawing component, suitable electron withdrawing componentsand addition amounts, impregnation with metals or metal ions (e.g.,zinc, nickel, vanadium, titanium, silver, copper, gallium, tin,tungsten, molybdenum, zirconium, and the like, or combinations thereof),and various calcining procedures and conditions are disclosed in, forexample, U.S. Pat. Nos. 6,107,230, 6,165,929, 6,294,494, 6,300,271,6,316,553, 6,355,594, 6,376,415, 6,388,017, 6,391,816, 6,395,666,6,524,987, 6,548,441, 6,548,442, 6,576,583, 6,613,712, 6,632,894,6,667,274, 6,750,302, 7,294,599, 7,601,665, 7,884,163, and 8,309,485,which are incorporated herein by reference in their entirety. Othersuitable processes and procedures for preparing activator-supports(e.g., fluorided solid oxides, sulfated solid oxides, etc.) are wellknown to those of skill in the art.

Co-Catalysts

In certain aspects directed to catalyst compositions containing aco-catalyst, the co-catalyst can comprise a metal hydrocarbyl compound,examples of which include non-halide metal hydrocarbyl compounds, metalhydrocarbyl halide compounds, non-halide metal alkyl compounds, metalalkyl halide compounds, and so forth. The hydrocarbyl group (or alkylgroup) can be any hydrocarbyl (or alkyl) group disclosed herein.Moreover, in some aspects, the metal of the metal hydrocarbyl can be agroup 1, 2, 11, 12, 13, or 14 metal; alternatively, a group 13 or 14metal; or alternatively, a group 13 metal. Hence, in some aspects, themetal of the metal hydrocarbyl (or non-halide metal hydrocarbyl or metalhydrocarbyl halide) can be lithium, sodium, potassium, rubidium, cesium,beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, boron,aluminum, or tin; alternatively, lithium, sodium, potassium, magnesium,calcium, zinc, boron, aluminum, or tin; alternatively, lithium, sodium,or potassium; alternatively, magnesium or calcium; alternatively,lithium; alternatively, sodium; alternatively, potassium; alternatively,magnesium; alternatively, calcium; alternatively, zinc; alternatively,boron; alternatively, aluminum; or alternatively, tin. In some aspects,the metal hydrocarbyl or metal alkyl, with or without a halide, cancomprise a lithium hydrocarbyl or alkyl, a magnesium hydrocarbyl oralkyl, a boron hydrocarbyl or alkyl, a zinc hydrocarbyl or alkyl, or analuminum hydrocarbyl or alkyl.

In particular aspects directed to catalyst compositions containing aco-catalyst (e.g., the activator can comprise a solid oxide treated withan electron-withdrawing anion), the co-catalyst can comprise analuminoxane compound (e.g., a supported aluminoxane), an organoboron ororganoborate compound, an ionizing ionic compound, an organoaluminumcompound, an organozinc compound, an organomagnesium compound, or anorganolithium compound, and this includes any combinations of thesematerials. In one aspect, the co-catalyst can comprise an organoaluminumcompound. In another aspect, the co-catalyst can comprise an aluminoxanecompound, an organoboron or organoborate compound, an ionizing ioniccompound, an organozinc compound, an organomagnesium compound, anorganolithium compound, or any combination thereof. In yet anotheraspect, the co-catalyst can comprise an aluminoxane compound;alternatively, an organoboron or organoborate compound; alternatively,an ionizing ionic compound; alternatively, an organozinc compound;alternatively, an organomagnesium compound; or alternatively, anorganolithium compound.

Specific non-limiting examples of suitable organoaluminum compounds caninclude trimethylaluminum (TMA), triethylaluminum (TEA),tri-n-propylaluminum (TNPA), tri-n-butylaluminum (TNBA),triisobutylaluminum (TIBA), tri-n-hexylaluminum, tri-n-octylaluminum,diisobutyl aluminum hydride, di ethyl aluminum ethoxide, diethylaluminumchloride, and the like, or combinations thereof. Representative andnon-limiting examples of aluminoxanes include methylaluminoxane,modified methylaluminoxane, ethylaluminoxane, n-propylaluminoxane,iso-propylaluminoxane, n-butylaluminoxane, t-butylaluminoxane,sec-butylaluminoxane, iso-butylaluminoxane, 1-pentyl aluminoxane,2-pentylaluminoxane, 3-pentyl aluminoxane, isopentyl aluminoxane,neopentylaluminoxane, and the like, or any combination thereof.Representative and non-limiting examples of organoboron/organoboratecompounds include N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, triphenylcarbeniumtetrakis(pentafluorophenyl)borate, lithiumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, triphenylcarbeniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate,tris(pentafluorophenyl)boron, tris[3,5-bis(trifluoromethyl)phenyl]boron,and the like, or mixtures thereof.

Examples of ionizing ionic compounds can include, but are not limitedto, the following compounds: tri(n-butyl)ammoniumtetrakis(p-tolyl)borate, tri(n-butyl) ammonium tetrakis(m-tolyl)borate,tri(n-butyl)ammonium tetrakis(2,4-dimethylphenyl)borate,tri(n-butyl)ammonium tetrakis(3,5-dimethylphenyl)borate,tri(n-butyl)ammonium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate,tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate,N,N-dimethylanilinium tetrakis(p-tolyl)borate, N,N-dimethylaniliniumtetrakis(m-tolyl)borate, N,N-dimethylaniliniumtetrakis(2,4-dimethylphenyl)borate, N,N-dimethylaniliniumtetrakis(3,5-dimethyl-phenyl)borate, N,N-dimethylaniliniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, triphenylcarbeniumtetrakis(p-tolyl)borate, triphenylcarbenium tetrakis(m-tolyl)borate,triphenylcarbenium tetrakis(2,4-dimethylphenyl)borate,triphenylcarbenium tetrakis(3,5-dimethylphenyl)borate,triphenylcarbenium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate,triphenylcarbenium tetrakis(pentafluorophenyl)borate, tropyliumtetrakis(p-tolyl)borate, tropylium tetrakis(m-tolyl)borate, tropyliumtetrakis(2,4-dimethylphenyl)borate, tropyliumtetrakis(3,5-dimethylphenyl)borate, tropyliumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, tropyliumtetrakis(pentafluorophenyl) borate, lithiumtetrakis(pentafluorophenyl)borate, lithium tetraphenylborate, lithiumtetrakis(p-tolyl)borate, lithium tetrakis(m-tolyl)borate, lithiumtetrakis(2,4-dim ethyl phenyl)borate, lithiumtetrakis(3,5-dimethylphenyl)borate, lithium tetrafluoroborate, sodiumtetrakis(pentafluorophenyl)borate, sodium tetraphenylborate, sodiumtetrakis(p-tolyl)borate, sodium tetrakis(m-tolyl)borate, sodiumtetrakis(2,4-dimethylphenyl)borate, sodiumtetrakis(3,5-dimethylphenyl)borate, sodium tetrafluoroborate, potassiumtetrakis(pentafluorophenyl)borate, potassium tetraphenylborate,potassium tetrakis(p-tolyl)borate, potassium tetrakis(m-tolyl)borate,potassium tetrakis(2,4-dimethylphenyl)borate, potassiumtetrakis(3,5-dimethylphenyl)borate, potassium tetrafluoroborate, lithiumtetrakis(pentafluorophenyl)aluminate, lithium tetraphenylaluminate,lithium tetrakis(p-tolyl)aluminate, lithium tetrakis(m-tolyl)aluminate,lithium tetrakis(2,4-dimethylphenyl)aluminate, lithiumtetrakis(3,5-dimethylphenyl)aluminate, lithium tetrafluoroaluminate,sodium tetrakis(pentafluorophenyl)aluminate, sodiumtetraphenylaluminate, sodium tetrakis(p-tolyl)aluminate, sodiumtetrakis(m-tolyl)aluminate, sodiumtetrakis(2,4-dimethylphenyl)aluminate, sodiumtetrakis(3,5-dimethylphenyl)aluminate, sodium tetrafluoroaluminate,potassium tetrakis(pentafluorophenyl)aluminate, potassiumtetraphenylaluminate, potassium tetrakis(p-tolyl)aluminate, potassiumtetrakis(m-tolyl)aluminate, potassiumtetrakis(2,4-dimethylphenyl)aluminate, potassiumtetrakis(3,5-dimethylphenyl)aluminate, potassium tetrafluoroaluminate,and the like, or combinations thereof.

Exemplary organozinc compounds which can be used as co-catalysts caninclude, but are not limited to, dimethylzinc, diethylzinc,dipropylzinc, dibutylzinc, dineopentylzinc, di(trimethylsilyl)zinc,di(triethylsilyl)zinc, di(triisoproplysilyl)zinc,di(triphenylsilyl)zinc, di(allyldimethylsilyl)zinc,di(trimethylsilylmethyl)zinc, and the like, or combinations thereof.

Similarly, exemplary organomagnesium compounds can include, but are notlimited to, dimethylmagnesium, diethylmagnesium, dipropylmagnesium,dibutylmagnesium, dineopentylmagnesium,di(trimethylsilylmethyl)magnesium, methylmagnesium chloride,ethylmagnesium chloride, propylmagnesium chloride, butylmagnesiumchloride, neopentylmagnesium chloride, trimethylsilylmethylmagnesiumchloride, methylmagnesium bromide, ethylmagnesium bromide,propylmagnesium bromide, butylmagnesium bromide, neopentylmagnesiumbromide, trimethylsilylmethylmagnesium bromide, methylmagnesium iodide,ethylmagnesium iodide, propylmagnesium iodide, butylmagnesium iodide,neopentylmagnesium iodide, trimethylsilylmethylmagnesium iodide,methylmagnesium ethoxide, ethylmagnesium ethoxide, propylmagnesiumethoxide, butylmagnesium ethoxide, neopentylmagnesium ethoxide,trimethyl silylmethylmagnesium ethoxide, methylmagnesium propoxide,ethylmagnesium propoxide, propylmagnesium propoxide, butylmagnesiumpropoxide, neopentylmagnesium propoxide, trimethylsilylmethylmagnesiumpropoxide, methylmagnesium phenoxide, ethylmagnesium phenoxide,propylmagnesium phenoxide, butylmagnesium phenoxide, neopentylmagnesiumphenoxide, trimethylsilylmethylmagnesium phenoxide, and the like, or anycombinations thereof.

Likewise, exemplary organolithium compounds can include, but are notlimited to, methyllithium, ethyllithium, propyllithium, butyllithium(e.g., t-butyllithium), neopentyllithium, trim ethyl silylmethyllithium,phenyllithium, tolyllithium, xylyllithium, benzyllithium,(dimethylphenyl)methyllithium, allyllithium, and the like, orcombinations thereof.

Co-catalysts that can be used in the catalyst compositions of thisinvention are not limited to the co-catalysts described above. Othersuitable co-catalysts are well known to those of skill in the artincluding, for example, those disclosed in U.S. Pat. Nos. 3,242,099,4,794,096, 4,808,561, 5,576,259, 5,807,938, 5,919,983, 7,294,5997,601,665, 7,884,163, 8,114,946, and 8,309,485, which are incorporatedherein by reference in their entirety.

Olefin Monomers and Olefin Polymers

Olefin monomers contemplated herein typically include olefin compoundshaving from 2 to 30 carbon atoms per molecule and having at least oneolefinic double bond. Homopolymerization processes using a singleolefin, such as ethylene, propylene, butene, hexene, octene, and thelike, are encompassed, as well as copolymerization andterpolymerization, reactions using an olefin monomer with at least onedifferent olefinic compound. For example, resultant ethylene copolymers,or terpolymers, generally can contain a major amount of ethylene (>50mole percent) and a minor amount of comonomer (<50 mole percent), thoughthis is not a requirement. Comonomers that can be copolymerized withethylene often can have from 3 to 20 carbon atoms, or from 3 to 10carbon atoms, in their molecular chain.

Acyclic, cyclic, polycyclic, terminal (a), internal, linear, branched,substituted, unsubstituted, functionalized, and non-functionalizedolefins can be employed. For example, typical unsaturated compounds thatcan be polymerized to produce olefin polymers can include, but are notlimited to, ethylene, propylene, 1-butene, 2-butene, 3-methyl-1-butene,isobutylene, 1-pentene, 2-pentene, 3-methyl-1-pentene,4-methyl-1-pentene, 1-hexene, 2-hexene, 3-hexene, 3-ethyl-1-hexene,1-heptene, 2-heptene, 3-heptene, the four normal octenes (e.g.,1-octene), the four normal nonenes, the five normal decenes, and thelike, or mixtures of two or more of these compounds. Cyclic and bicyclicolefins, including but not limited to, cyclopentene, cyclohexene,norbornylene, norbornadiene, and the like, also can be polymerized asdescribed herein. Styrene also can be employed as a monomer or as acomonomer. In an aspect, the olefin monomer can comprise a C₂-C₂₀olefin; alternatively, a C₂-C₂₀ α-olefin; alternatively, a C₂-C₁₂olefin; alternatively, a C₂-C₁₀ α-olefin; alternatively, ethylene,propylene, 1-butene, 1-hexene, or 1-octene; alternatively, ethylene orpropylene; alternatively, ethylene; or alternatively, propylene.

When a copolymer (or alternatively, a terpolymer) is desired, the olefinmonomer can be, for example, ethylene or propylene, which iscopolymerized with at least one comonomer (e.g., a C₂-C₂₀ α-olefin, aC₃-C₂₀ α-olefin). According to one aspect, the olefin monomer in thepolymerization process can be ethylene. In this aspect, examples ofsuitable olefin comonomers can include, but are not limited to,propylene, 1-butene, 2-butene, 3-methyl-1-butene, isobutylene,1-pentene, 2-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene,2-hexene, 3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene, 1-octene,1-decene, styrene, and the like, or combinations thereof. According toanother aspect, the comonomer can comprise an α-olefin (e.g., a C₃-C₁₀α-olefin), while in yet another aspect, the comonomer can comprise1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, styrene, or anycombination thereof. For example, the comonomer can comprise 1-butene,1-hexene, 1-octene, or a combination thereof alternatively, thecomonomer can comprise 1-butene; alternatively, the comonomer cancomprise 1-hexene; or alternatively, the comonomer can comprise1-octene.

Generally, the amount of comonomer introduced into a polymerizationreactor to produce the copolymer can be from about 0.01 to about 50weight percent of the comonomer based on the total weight of the monomerand comonomer. According to another aspect, the amount of comonomerintroduced into a polymerization reactor can be from about 0.01 to about40 weight percent comonomer based on the total weight of the monomer andcomonomer. In still another aspect, the amount of comonomer introducedinto a polymerization reactor can be from about 0.1 to about 35 weightpercent comonomer based on the total weight of the monomer andcomonomer. Yet, in another aspect, the amount of comonomer introducedinto a polymerization reactor can be from about 0.5 to about 20 weightpercent comonomer based on the total weight of the monomer andcomonomer.

While not intending to be bound by this theory, where branched,substituted, or functionalized olefins are used as reactants, it isbelieved that a steric hindrance can impede and/or slow thepolymerization reaction. Thus, branched and/or cyclic portion(s) of theolefin removed somewhat from the carbon-carbon double bond would not beexpected to hinder the reaction in the way that the same olefinsubstituents situated more proximate to the carbon-carbon double bondmight.

According to one aspect, at least one monomer/reactant can be ethylene(or propylene), so the polymerization reaction can be ahomopolymerization involving only ethylene (or propylene), or acopolymerization with a different acyclic, cyclic, terminal, internal,linear, branched, substituted, or unsubstituted olefin. In addition, themethods disclosed herein intend for olefin to also encompass diolefincompounds that include, but are not limited to, 1,3-butadiene, isoprene,1,4-pentadiene, 1,5-hexadiene, and the like.

Olefin polymers encompassed herein can include any polymer (or oligomer)produced from any olefin monomer (and optional comonomer(s)) describedherein. For example, the olefin polymer can comprise an ethylenehomopolymer, a propylene homopolymer, an ethylene copolymer (e.g.,ethylene/α-olefin, ethylene/1-butene, ethylene/1-hexene, orethylene/1-octene), a propylene copolymer, an ethylene terpolymer, apropylene terpolymer, and the like, including combinations thereof. Inone aspect, the olefin polymer can be (or can comprise) an ethylenehomopolymer, an ethylene/1-butene copolymer, an ethylene/1-hexenecopolymer, or an ethyl ene/l-octene copolymer; or alternatively, anethylene/1-hexene copolymer. In another aspect, the olefin polymer canbe (or can comprise) a polypropylene homopolymer or a propylene-basedcopolymer. In some aspects, the olefin polymer can have a bimodalmolecular weight distribution, while in other aspects, the olefinpolymer can have a multimodal molecular weight distribution. Yet, instill other aspects, the olefin polymer can have a unimodal molecularweight distribution.

Polymerization Reactor Systems and Processes

The disclosed catalyst systems and methods of their preparation areintended for any olefin polymerization process using various types ofpolymerization reactors, polymerization reactor systems, andpolymerization reaction conditions. As used herein, “polymerizationreactor” includes any polymerization reactor capable of polymerizingolefin monomers and comonomers (one or more than one comonomer) toproduce homopolymers, copolymers, terpolymers, and the like. The varioustypes of polymerization reactors include, but are not limited to, thosethat can be referred to as a batch reactor, slurry reactor, gas-phasereactor, solution reactor, high pressure reactor, tubular reactor,autoclave reactor, and the like, or combinations thereof. Suitablepolymerization conditions are used for the various reactor types. Gasphase reactors can comprise fluidized bed reactors or staged horizontalreactors. Slurry reactors can comprise vertical or horizontal loops.High pressure reactors can comprise autoclave reactors, tubularreactors, or combinations thereof, in parallel or in series. Reactortypes can include batch or continuous processes. Continuous processescan use intermittent or continuous product discharge. Polymerizationreactor systems and processes also can include partial or full directrecycle of unreacted monomer, unreacted comonomer, and/or diluent.

A polymerization reactor system can comprise a single reactor ormultiple reactors (for example, 2 reactors, or more than 2 reactors) ofthe same or different type. For example, the polymerization reactorsystem can comprise a slurry reactor, a gas-phase reactor, a solutionreactor, or a combination of two or more of these reactors. Productionof polymers in multiple reactors can include several stages in at leasttwo separate polymerization reactors interconnected by at least onetransfer device, making it possible to transfer the polymers resultingfrom the first polymerization reactor into the second reactor. Thedesired polymerization conditions in one of the reactors can bedifferent from the operating conditions of the other reactor(s).Alternatively, polymerization in multiple reactors can include themanual transfer of polymer from one reactor to subsequent reactors forcontinued polymerization. Multiple reactor systems can include anycombination including, but not limited to, multiple loop reactors,multiple gas phase reactors, a combination of loop and gas phasereactors, multiple high pressure reactors, or a combination of highpressure with loop and/or gas phase reactors. The multiple reactors canbe operated in series, in parallel, or both.

According to one aspect, the polymerization reactor system can compriseat least one loop slurry reactor comprising vertical or horizontalloops. Monomer, diluent, catalyst, and comonomer can be continuously fedinto a loop reactor where polymerization occurs. Generally, continuousprocesses can comprise the continuous introduction of monomer/comonomer,a catalyst, and a diluent into a polymerization reactor and thecontinuous removal from this reactor of a suspension comprising polymerparticles and the diluent. Reactor effluent can be flashed to remove thesolid polymer from the liquids that comprise the diluent, monomer and/orcomonomer. Various technologies can be used for this separation stepincluding, but not limited to, flashing that can include any combinationof heat addition and pressure reduction, separation by cyclonic actionin either a cyclone or hydrocyclone, or separation by centrifugation.

A typical slurry polymerization process (also known as the particle formprocess) is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, 6,833,415, and8,822,608, each of which is incorporated herein by reference in itsentirety.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under polymerization conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used, such as can be employed in the bulkpolymerization of propylene to form polypropylene homopolymers.

According to yet another aspect, the polymerization reactor system cancomprise at least one gas phase reactor (e.g., a fluidized bed reactor).Such reactor systems can employ a continuous recycle stream containingone or more monomers continuously cycled through a fluidized bed in thepresence of the catalyst under polymerization conditions. A recyclestream can be withdrawn from the fluidized bed and recycled back intothe reactor. Simultaneously, polymer product can be withdrawn from thereactor and new or fresh monomer can be added to replace the polymerizedmonomer. Such gas phase reactors can comprise a process for multi-stepgas-phase polymerization of olefins, in which olefins are polymerized inthe gaseous phase in at least two independent gas-phase polymerizationzones while feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone. Representative gasphase reactors are disclosed in U.S. Pat. Nos. 5,352,749, 4,588,790,5,436,304, 7,531,606, and 7,598,327, each of which is incorporated byreference in its entirety herein.

According to still another aspect, the polymerization reactor system cancomprise a high pressure polymerization reactor, e.g., can comprise atubular reactor and/or an autoclave reactor. Tubular reactors can haveseveral zones where fresh monomer, initiators, or catalysts are added.Monomer can be entrained in an inert gaseous stream and introduced atone zone of the reactor. Initiators, catalysts, and/or catalystcomponents can be entrained in a gaseous stream and introduced atanother zone of the reactor. The gas streams can be intermixed forpolymerization. Heat and pressure can be employed appropriately toobtain optimal polymerization reaction conditions.

According to yet another aspect, the polymerization reactor system cancomprise a solution polymerization reactor wherein the monomer/comonomerare contacted with the catalyst composition by suitable stirring orother means. A carrier comprising an inert organic diluent or excessmonomer can be employed. If desired, the monomer/comonomer can bebrought in the vapor phase into contact with the catalytic reactionproduct, in the presence or absence of liquid material. Thepolymerization zone can be maintained at temperatures and pressures thatwill result in the formation of a solution of the polymer in a reactionmedium. Agitation can be employed to obtain better temperature controland to maintain uniform polymerization mixtures throughout thepolymerization zone. Adequate means are utilized for dissipating theexothermic heat of polymerization.

The polymerization reactor system can further comprise any combinationof at least one raw material feed system, at least one feed system forcatalyst or catalyst components, and/or at least one polymer recoverysystem. Suitable reactor systems can further comprise systems forfeedstock purification, catalyst storage and preparation, extrusion,reactor cooling, polymer recovery, fractionation, recycle, storage,loadout, laboratory analysis, and process control.

Polymerization conditions that can be controlled for efficiency and toprovide desired polymer properties can include temperature, pressure,and the concentrations of various reactants. Polymerization temperaturecan affect catalyst productivity, polymer molecular weight, andmolecular weight distribution. A suitable polymerization temperature canbe any temperature below the de-polymerization temperature according tothe Gibbs Free energy equation. Typically, the polymerizationtemperature is in a range from about 35° C. to about 280° C., forexample, or from about 50° C. to about 175° C., depending upon the typeof polymerization reactor(s). In some reactor systems, thepolymerization temperature generally can fall within a range from about60° C. to about 120° C., or from about 70° C. to about 100° C. Variouspolymerization conditions can be held substantially constant, forexample, for the production of a particular grade of olefin polymer.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor is typically less than 1000 psig (6.9 MPa). The pressurefor gas phase polymerization is usually at about 200 to 500 psig (1.4MPa to 3.4 MPa). High pressure polymerization in tubular or autoclavereactors is generally conducted at about 20,000 to 75,000 psig (138 to517 MPa). Polymerization reactors can also be operated in asupercritical region occurring at generally higher temperatures andpressures (for instance, above 92° C. and 700 psig (4.83 MPa)).Operation above the critical point of a pressure/temperature diagram(supercritical phase) can offer advantages to the polymerizationreaction process.

Also encompassed herein are olefin polymerization processes utilizingany of the catalyst compositions described herein. One such process cancomprise contacting a catalyst composition with an olefin monomer andoptionally an olefin comonomer in a polymerization reactor system underpolymerization conditions to produce an olefin polymer. Generally, thepolymerization process can utilize any olefin monomer and optionalcomonomer disclosed herein, and the catalyst composition employed can bea single (or dual) metallocene catalyst system utilizing, for instance,any of the metallocene compounds, any of activators, and any of theco-catalysts disclosed herein, and the catalyst system can be preparedby any of the processes disclosed herein.

This invention is also directed to, and encompasses, the polymersproduced by any of the polymerization processes disclosed herein.Articles of manufacture can be formed from, and/or can comprise, thepolymers (e.g., ethylene copolymers) of this invention and, accordingly,are encompassed herein. For example, articles that can comprise polymersof this invention include, but are not limited to, an agricultural film,an automobile part, a bottle, a drum, a fiber or fabric, a foodpackaging film or container, a food service article, a fuel tank, ageomembrane, a household container, a liner, a molded product, a medicaldevice or material, a pipe, a sheet or tape, a toy, and the like.Various processes can be employed to form these articles. Non-limitingexamples of these processes include injection molding, blow molding,rotational molding, film extrusion, sheet extrusion, profile extrusion,thermoforming, and the like. Additionally, additives and modifiers areoften added to these polymers in order to provide beneficial polymerprocessing or end-use product attributes. Such processes and materialsare described in Modern Plastics Encyclopedia, Mid-November 1995 Issue,Vol. 72, No. 12; and Film Extrusion Manual—Process, Materials,Properties, TAPPI Press, 1992; the disclosures of which are incorporatedherein by reference in their entirety.

Also contemplated herein is a method for forming or preparing an articleof manufacture comprising a polymer produced by any of thepolymerization processes disclosed herein. For instance, a method cancomprise (i) contacting any catalyst composition disclosed herein withan olefin monomer and an optional olefin comonomer under polymerizationconditions in a polymerization reactor system to produce an olefinpolymer (the catalyst composition can be prepared in accordance with anyprocess disclosed herein); and (ii) forming an article of manufacturecomprising the olefin polymer. The forming step can comprise blending,melt processing, extruding, molding, or thermoforming, and the like,including combinations thereof.

EXAMPLES

Aspects of the invention are further illustrated by the followingexamples, which are not to be construed in any way as imposinglimitations to the scope of the invention described herein. Variousother aspects, modifications, and equivalents thereof which, afterreading the description herein, can suggest themselves to one ofordinary skill in the art without departing from the spirit of thepresent invention or the scope of the appended claims.

Sulfated alumina activator-supports were prepared as follows. Bohemitewas obtained from W.R. Grace & Company under the designation “Alumina A”and having a surface area of 300 m²/g, a pore volume of 1.3 mL/g, and anaverage particle size of 100 microns. This material was impregnated toincipient wetness with an aqueous solution of ammonium sulfate to equal15 wt. % sulfate. The pore filling or “incipient wetness” impregnationtechnique used is a method in which the solution is mixed with the drysupport until the pores are filled. The definition of the end point ofthis method can vary somewhat from laboratory to laboratory so that animpregnated catalyst could have a completely dry appearance or a stickysnow-like appearance. However, there is no free-flowing liquid presentwhen the incipient wetness method is employed. The impregnated materialwas then placed in a flat pan and allowed to dry under vacuum at 110° C.for 16 hr. To calcine the resultant powdered mixture, the material wasfluidized in a stream of dry air at 550° C. for 6 hr. Afterward, thesulfated alumina was collected and stored under dry nitrogen, and wasused without exposure to the atmosphere.

Fluorided silica-coated alumina activator-supports were prepared asfollows. Alumina A was first calcined in dry air at 600° C. for 6 hr,cooled to ambient temperature, and then contacted withtetraethylorthosilicate in isopropanol to equal 25 wt. % SiO₂. Afterdrying, the silica-coated alumina was calcined at 600° C. for 3 hr.Fluorided silica-coated alumina (7 wt. % F) was prepared by impregnatingthe calcined silica-coated alumina with an ammonium bifluoride solutionin methanol, drying, and then calcining for 3 hr at 600° C. in dry air.Afterward, the fluorided silica-coated alumina was collected and storedunder dry nitrogen, and was used without exposure to the atmosphere.

Polymerization experiments were performed as follows. First, 0.4 mmol oftriisobutylaluminum (TIBA, 0.4 mL of a 1M solution in heptane) wereadded to an autoclave reactor while venting isobutane vapor. Next,approximately 100 mg of fluorided silica-coated alumina (sulfatedalumina was used for Example 1) were added to the reactor, followed by ametallocene solution containing 1 mg (2 mg were used for Example 1) ofmetallocene M1 in toluene. The reactor contents were mixed, the chargeport was closed, and 2 L of isobutane were added to the reactor. Thecontents of the reactor were stirred and heated to the desiredpolymerization reaction temperature of 90° C., and ethylene was thenintroduced into the reactor (no hydrogen or comonomer was used).Ethylene was fed on demand to maintain the target pressure of 390 psigpressure for the 30 min length of each polymerization experiment. Thereactor was maintained at the desired reaction temperature throughoutthe experiment by an automated heating-cooling system.

The chemical structure for metallocene M1 is provided below(t-Bu=tert-butyl; Me=methyl):

Examples 1-7

Table I summarizes Examples 1-7. In Comparative Examples 1-4,approximately 10-20 mg of solid M1 were placed in a flask, and exposedto air at 25-30° C. for 4-24 hr at 45% relative humidity (Examples 1-3)or for 13 hr at 80% relative humidity (Example 4). Then, toluene wasadded to the flask to dissolve the exposed solid M1 at a 1 mg/mLconcentration. A sample of the M1 solution in toluene was testedimmediately (shelf time of “zero” hr) for catalyst activity (amount ofsolid PE product produced in 30 min) using the standard polymerizationprocedure described above, while the remaining solution in the flask wasstored under nitrogen at 25-30° C. for the respective shelf timesindicated in Table I. After storage for 24-26 hr, the catalyst activityof the exposed metallocenes in Examples 1-4 decreased significantly,where at least 65% to over 90% of the catalyst activity was lost due toair exposure of the M1 solid, and storage in a toluene solution for 1day. Additionally, a visible color change of the solution was noted,from an initial yellow/brown color to a light or pale yellow color.Solutions of the exposed metallocene were unstable, had a shortshelf-life, and resulted in poor catalyst activity (i.e., the exposedmetallocenes were unusable).

Examples 5-7 were conducted in the same manner as Comparative Examples1-4, with the respective exposure conditions (13-19 hr, 45%-80% relativehumidity) shown in Table I. After exposure, however, the solid M1 in theflask was purged with nitrogen at 25-30° C. for the time period in TableI prior to the addition of toluene to the flask (1 mg of M1 per mL oftoluene) and storage under nitrogen for the respective shelf timesindicated in Table I. The standard polymerization procedure describedabove was used to test solutions of M1 at the indicated shelf times.Unexpectedly, after storage of the toluene solution at 25-30° C. for24-48 hr, no visible color change was noted, and the catalyst activitywas effectively unchanged; on average, there was a difference incatalyst activity of less than 10%. Solutions of the treated metallocenewere stable, had a long shelf-life, and resulted in excellent catalystactivity (i.e., comparable to the fresh metallocene).

Examples 8-13

Example 8 was a control experiment, in which the solid M1 was stored ina flask under nitrogen, with no exposure to air, prior to addition oftoluene to the flask (1 mg M1 per mL toluene). Consequently, catalystactivity was relatively stable over a period of 24-72 hr. ComparativeExample 9 was conducted in the same manner as Comparative Examples 1-4,with the respective exposure conditions, shelf times, and catalystactivity shown in Table II. Similar to Comparative Examples 1-4, afterstorage of the toluene solution at 25-30° C. for 26 hr, the catalystactivity was a fraction of the initial catalyst activity: over 90% ofthe catalyst activity was lost due to air exposure of the M1 solid, andstorage in a toluene solution for 1 day. The solution of the exposedmetallocene was unstable, had a short shelf-life, and resulted in poorcatalyst activity (i.e., the exposed metallocene was unusable).

In Examples 10-13, solid M1 was exposed to air at 25-30° C. for 8-72 hrat 80% relative humidity in the flask, followed by the nitrogen purgingcycles (at 25-30° C.) and vacuum cycles (pressure of 0.5 torr) indicatedin Table II, prior to the addition of toluene to the flask (1 mg M1 permL toluene) and storage under nitrogen for the respective shelf timesindicated in Table II. The standard polymerization procedure describedabove was used to test solutions of M1 at the indicated shelf times.Unexpectedly, after storage of the toluene solution at 25-30° C. for24-72 hr, the catalyst activity was effectively unchanged. Solutions ofthe treated metallocene were stable, had a long shelf-life, and resultedin excellent catalyst activity (i.e., comparable to the freshmetallocene).

For solid metallocenes exposed to high moisture conditions for longperiods of time, it was noted that nitrogen purging alone may notcompletely restore catalyst activity, shelf-life, and stability, andthat a combination of purging and vacuum treatment may provide superiorresults.

TABLE I Examples 1-7. M1 exposed Treatment of Shelf time Solid PEExample Type to air exposed M1 (hr) (g) 1 Comparative 19 hr at ~45% No 0142 humidity 24 3 2 Comparative 4 hr at ~45% No 0 332 humidity 24 110 3Comparative 24 hr at ~45% No 0 320 humidity 2 193 26 15 4 Comparative 13hr at ~80% No 0 315 humidity 4 215 24 24 5 Inventive 19 hr at ~45%Purged M1 with 2 415 humidity nitrogen for 2 days 26 395 6 Inventive 13hr at ~45% Purged M1 with 0 368 humidity nitrogen for 6 hr 27 413 48 3497 Inventive 13 hr at ~80% Purged M1 with 0 354 humidity nitrogen for 8hr 24 291

TABLE II Examples 8-13. M1 exposed Treatment of Shelf time Solid ExampleType to air exposed M1 (hr) PE (g) 8 Control No No 0 266 24 248 48 23472 216 9 Comparative 8 hr at ~80% No 0 246 humidity 26 14 10 Inventive 8hr at ~80% Purged M1 with nitrogen 0 279 humidity for 30 min, thenvacuum 24 278 treated for 30 min. 48 256 Repeated this process 3 72 251times. Then, vacuum treated for an additional 2 hr. 11 Inventive 8 hr at~80% Purged M1 with nitrogen 0 227 humidity for 30 min, then vacuum 26227 treated for 30 min. 72 225 Repeated this process 3 times. Then,vacuum treated for an additional 2 hr. 12 Inventive 24 hr at ~80% PurgedM1 with nitrogen 0 256 humidity for 30 min, then vacuum 24 267 treatedfor 30 min. 48 292 Repeated this process 3 72 233 times. Then, vacuumtreated for an additional 2 hr. 13 Inventive 72 hr at ~80% Purged M1with nitrogen 0 282 humidity for 30 min, then vacuum 24 299 treated for30 min. 48 297 Repeated this process 3 72 259 times. Then, vacuumtreated for an additional 2 hr.

The invention is described above with reference to numerous aspects andspecific examples. Many variations will suggest themselves to thoseskilled in the art in light of the above detailed description. All suchobvious variations are within the full intended scope of the appendedclaims. Other aspects of the invention can include, but are not limitedto, the following (aspects are described as “comprising” but,alternatively, can “consist essentially of” or “consist of”):

Aspect 1. A method for treating an exposed solid metallocene compound,the method comprising:

contacting the exposed solid metallocene compound with a purging gasstream comprising an inert gas to form a treated solid metallocenecompound.

Aspect 2. A method for treating an exposed solid metallocene compound,the method comprising, in any order:

contacting the exposed solid metallocene compound with a purging gasstream comprising an inert gas; and

subjecting the exposed solid metallocene compound to a sub-atmosphericpressure;

to form a treated solid metallocene compound.

Aspect 3. The method defined in aspect 1 or 2, wherein the purging gasstream comprises any suitable inert gas, or any inert gas disclosedherein, for example, helium, neon, argon, nitrogen, or any combinationthereof.

Aspect 4. The method defined in any one of the preceding aspects,wherein the purging gas stream is substantially free ofoxygen-containing compounds, for example, less than 25 ppmw (ppm byweight).

Aspect 5. The method defined in any one of the preceding aspects,wherein the purging gas stream is substantially free of water, forexample, less than 25 ppmw.

Aspect 6. The method defined in any one of the preceding aspects,wherein the method is conducted under conditions sufficient to reach atleast 80%, at least 85%, or at least 90%, of the catalyst activity of afresh solid metallocene compound, after 24 hours in a toluene solution,under the same polymerization conditions.

Aspect 7. The method defined in any one of the preceding aspects,wherein the method is conducted under conditions sufficient to maintainthe color of a 1 mg/mL solution of the treated solid metallocenecompound for at least 24 hours at 25° C.

Aspect 8. The method defined in any one of the preceding aspects,wherein the purging step is conducted at a purging temperature in anypurging temperature range disclosed herein, for example, from about 0°C. to about 100° C., from about 10° C. to about 75° C., or from about15° C. to about 50° C.

Aspect 9. The method defined in any one of the preceding aspects,wherein the purging step is conducted for a time period in any range ofpurging time periods disclosed herein, for example, from about 30 min toabout 48 hours, from about 1 to about 12 hours, from about 30 min toabout 3 hours, or from about 1 to about 6 hours.

Aspect 10. The method defined in any one of the preceding aspects,wherein the purging step is conducted for a time period sufficient toreach at least 80%, at least 85%, or at least 90%, of the catalystactivity of a fresh solid metallocene compound, after 24 hours in atoluene solution, under the same polymerization conditions.

Aspect 11. The method defined in any one of the preceding aspects,wherein the purging step is conducted for a time period sufficient tomaintain the color of a 1 mg/mL solution of the treated solidmetallocene compound for at least 24 hours at 25° C.

Aspect 12. The method defined in any one of the preceding aspects,wherein the purging step comprises fluidizing the exposed solidmetallocene compound with the purging gas stream.

Aspect 13. The method defined in any one of aspects 2-12, wherein thesub-atmospheric pressure comprises any suitable sub-atmosphericpressure, or any sub-atmospheric pressure disclosed herein, for example,from about 100 to about 0.01 torr, from about 10 to about 0.1 torr, orfrom about 1 to about 0.1 torr.

Aspect 14. The method defined in any one of aspects 2-13, wherein thesubjecting step is conducted for a time period in any range of vacuumtime periods disclosed herein, for example, from about 30 min to about48 hours, from about 1 to about 12 hours, from about 30 min to about 3hours, or from about 1 to about 6 hours.

Aspect 15. The method defined in any one of aspects 2-14, wherein thesubjecting step is conducted at a vacuum temperature in any vacuumtemperature range disclosed herein, for example, from about 0° C. toabout 100° C., from about 10° C. to about 75° C., or from about 15° C.to about 50° C.

Aspect 16. The method defined in any one of the preceding aspects,wherein the method comprises any number of contacting (purging) cyclesdisclosed herein (for example, from 1 to 6, or from 2 to 4), and/or anynumber of subjecting (vacuum) cycles disclosed herein (for example, from1 to 6, or from 2 to 4), and performed in any order or sequence.

Aspect 17. The method defined in any one of the preceding aspects,wherein the method does not comprise a recrystallization step.

Aspect 18. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedmetallocene compound, for example, any bridged metallocene compounddisclosed herein.

Aspect 19. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedzirconium based metallocene compound with a fluorenyl group, and with noaryl groups on the bridging group.

Aspect 20. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedzirconium based metallocene compound with a cyclopentadienyl group and afluorenyl group, and with no aryl groups on the bridging group.

Aspect 21. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedzirconium or hafnium based metallocene compound with a fluorenyl group,and an aryl group on the bridging group.

Aspect 22. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedzirconium or hafnium based metallocene compound with a cyclopentadienylgroup and fluorenyl group, and an aryl group on the bridging group.

Aspect 23. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedzirconium based metallocene compound with a fluorenyl group, and an arylgroup on the bridging group.

Aspect 24. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedhafnium based metallocene compound with a fluorenyl group, and an arylgroup on the bridging group.

Aspect 25. The method defined in any one of aspects 21-24, wherein thearyl group is a phenyl group.

Aspect 26. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedzirconium or hafnium based metallocene compound with a cyclopentadienylgroup and a fluorenyl group, and with an alkenyl substituent.

Aspect 27. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedzirconium or hafnium based metallocene compound with two indenyl groups.

Aspect 28. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises a bridgedzirconium based metallocene compound with two indenyl groups.

Aspect 29. The method defined in any one of aspects 27-28, wherein thebridging group contains a silicon atom.

Aspect 30. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises an unbridgedmetallocene compound, for example, any unbridged metallocene compounddisclosed herein.

Aspect 31. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises an unbridgedzirconium or hafnium based metallocene compound containing twocyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl andan indenyl group.

Aspect 32. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises an unbridgedzirconium based metallocene compound containing two cyclopentadienylgroups, two indenyl groups, or a cyclopentadienyl and an indenyl group.

Aspect 33. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises an unbridgedzirconium based homodinuclear metallocene compound.

Aspect 34. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises an unbridgedhafnium based homodinuclear metallocene compound.

Aspect 35. The method defined in any one of aspects 1-17, wherein themetallocene compound (exposed, treated, fresh) comprises an unbridgedheterodinuclear metallocene compound.

Aspect 36. A treated solid metallocene compound prepared by the methoddefined in any one of the preceding aspects, wherein a 1 mg/mL solutionof the treated solid metallocene compound has a moisture level of lessthan 10 ppmw.

Aspect 37. A process to produce a catalyst composition, the processcomprising contacting, in any order:

(a) the treated solid metallocene compound defined in aspect 36;

(b) an activator; and

(c) optionally, a co-catalyst;

to produce the catalyst composition.

Aspect 38. The process defined in aspect 37, wherein the treated solidmetallocene compound is present as a slurry in a diluent.

Aspect 39. The process defined in aspect 37, wherein the treated solidmetallocene compound is present as a metallocene solution.

Aspect 40. The process defined in any one of aspects 37-39, wherein theactivator comprises an aluminoxane compound.

Aspect 41. The process defined in any one of aspects 37-39, wherein theactivator comprises an organoboron or organoborate compound.

Aspect 42. The process defined in any one of aspects 37-39, wherein theactivator comprises an ionizing ionic compound.

Aspect 43. The process defined in any one of aspects 37-39, wherein theactivator comprises an activator-support comprising a solid oxidetreated with an electron-withdrawing anion, for example, comprising anysolid oxide treated with any electron-withdrawing anion disclosedherein.

Aspect 44. The process defined in aspect 43, wherein the solid oxidecomprises silica, alumina, silica-alumina, silica-coated alumina,aluminum phosphate, aluminophosphate, heteropolytungstate, titania,zirconia, magnesia, boria, zinc oxide, a mixed oxide thereof, or anymixture thereof; and the electron-withdrawing anion comprises sulfate,bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate,fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate,fluorozirconate, fluorotitanate, phospho-tungstate, or any combinationthereof.

Aspect 45. The process defined in aspect 43, wherein theactivator-support comprises a fluorided solid oxide, a sulfated solidoxide, a phosphated solid oxide, or a combination thereof.

Aspect 46. The process defined in aspects 43, wherein theactivator-support comprises fluorided alumina, chlorided alumina,bromided alumina, sulfated alumina, phosphated alumina, fluoridedsilica-alumina, chlorided silica-alumina, bromided silica-alumina,sulfated silica-alumina, phosphated silica-alumina, fluoridedsilica-zirconia, chlorided silica-zirconia, bromided silica-zirconia,sulfated silica-zirconia, fluorided silica-titania, fluoridedsilica-coated alumina, sulfated silica-coated alumina, phosphatedsilica-coated alumina, or any combination thereof.

Aspect 47. The process defined in aspect 43, wherein theactivator-support comprises fluorided alumina, fluorided silica-alumina,fluorided silica-zirconia, fluorided silica-coated alumina,fluorided-chlorided silica-coated alumina, or any combination thereof.

Aspect 48. The process defined in aspect 43, wherein theactivator-support comprises sulfated alumina, sulfated silica-alumina,sulfated silica-coated alumina, or any combination thereof.

Aspect 49. The process defined in any one of aspects 37-48, wherein thecatalyst composition comprises any suitable co-catalyst, or anyco-catalyst disclosed herein.

Aspect 50. The process defined in any one of aspects 37-49, wherein theco-catalyst comprises any organoaluminum compound disclosed herein.

Aspect 51. The process defined in aspect 50, wherein the organoaluminumcompound comprises trimethylaluminum, triethylaluminum,tri-n-propylaluminum, tri-n-butyl aluminum, triisobutylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, diisobutyl aluminum hydride,diethyl aluminum ethoxide, di ethyl aluminum chloride, or anycombination thereof.

Aspect 52. A catalyst composition produced by the process defined in anyone of aspects 37-51.

Aspect 53. An olefin polymerization process, the process comprisingcontacting the catalyst composition defined in aspect 52 with an olefinmonomer and an optional olefin comonomer in a polymerization reactorsystem under polymerization conditions to produce an olefin polymer.

Aspect 54. The process defined in aspect 53, wherein the olefin monomercomprises any olefin monomer disclosed herein, for example, any C₂-C₂₀olefin.

Aspect 55. The process defined in aspect 53, wherein the olefin monomerand the optional olefin comonomer independently comprise a C₂-C₂₀alpha-olefin.

Aspect 56. The process defined in any one of aspects 53-55, wherein theolefin monomer comprises ethylene.

Aspect 57. The process defined in any one of aspects 53-56, wherein thecatalyst composition is contacted with ethylene and an olefin comonomercomprising a C₃-C₁₀ alpha-olefin.

Aspect 58. The process defined in any one of aspects 53-57, wherein thecatalyst composition is contacted with ethylene and an olefin comonomercomprising 1-butene, 1-hexene, 1-octene, or a mixture thereof.

Aspect 59. The process defined in any one of aspects 53-55, wherein theolefin monomer comprises propylene.

Aspect 60. The process defined in any one of aspects 53-59, wherein thepolymerization reactor system comprises a batch reactor, a slurryreactor, a gas-phase reactor, a solution reactor, a high pressurereactor, a tubular reactor, an autoclave reactor, or a combinationthereof.

Aspect 61. The process defined in any one of aspects 53-60, wherein thepolymerization reactor system comprises a slurry reactor, a gas-phasereactor, a solution reactor, or a combination thereof.

Aspect 62. The process defined in any one of aspects 53-61, wherein thepolymerization reactor system comprises a loop slurry reactor.

Aspect 63. The process defined in any one of aspects 53-62, wherein thepolymerization reactor system comprises a single reactor.

Aspect 64. The process defined in any one of aspects 53-62, wherein thepolymerization reactor system comprises 2 reactors.

Aspect 65. The process defined in any one of aspects 53-62, wherein thepolymerization reactor system comprises more than 2 reactors.

Aspect 66. The process defined in any one of aspects 53-65, wherein theolefin polymer comprises any olefin polymer disclosed herein.

Aspect 67. The process defined in any one of aspects 53-58 or 60-66,wherein the olefin polymer comprises an ethylene homopolymer, anethylene/1-butene copolymer, an ethylene/1-hexene copolymer, or anethylene/1-octene copolymer.

Aspect 68. The process defined in any one of aspects 53-58 or 60-66,wherein the olefin polymer comprises an ethylene/1-hexene copolymer.

Aspect 69. The process defined in any one of aspects 59-66, wherein theolefin polymer comprises a polypropylene homopolymer or apropylene-based copolymer.

We claim:
 1. A method for treating an exposed solid metallocenecompound, the method comprising, in any order: contacting the exposedsolid metallocene compound with a purging gas stream comprising an inertgas; and subjecting the exposed solid metallocene compound to asub-atmospheric pressure; to form a treated solid metallocene compound.2. The method of claim 1, wherein subjecting the exposed solidmetallocene compound to a sub-atmospheric pressure comprises: a pressurein a range from about 100 torr to about 0.01 torr; and a temperature ina range from about 10° C. to about 75° C.
 3. The method of claim 1,wherein the method comprises at least two contacting steps and at leasttwo subjecting steps, performed in any order.
 4. The method of claim 1,wherein a 1 mg/mL solution of the treated solid metallocene compound intoluene has a moisture content of less than 10 ppmw.
 5. The method ofclaim 1, wherein a color of a 1 mg/mL solution of the treated solidmetallocene compound in toluene is unchanged for a time period of 24hours at 25° C.
 6. The method of claim 1, wherein a catalyst activity ofa 1 mg/mL solution of the treated solid metallocene compound in tolueneis at least 85% of the catalyst activity obtained by using a 1 mg/mLsolution of a fresh solid metallocene compound in toluene, after a timeperiod of 24 hours at 25° C., under the same catalyst preparation andpolymerization conditions.
 7. A method for treating an exposed solidmetallocene compound, the method comprising: contacting the exposedsolid metallocene compound with a purging gas stream comprising an inertgas to form a treated solid metallocene compound.
 8. The method of claim7, wherein: the inert gas comprises nitrogen; the purging gas streamcomprises less than 25 ppmw of water; and the purging gas streamcomprises less than 25 ppmw of oxygen-containing compounds.
 9. Themethod of claim 7, wherein the method does not comprise arecrystallization step.
 10. The method of claim 7, wherein the treatedsolid metallocene compound comprises an unbridged zirconium or hafniumbased metallocene compound containing two cyclopentadienyl groups, twoindenyl groups, or a cyclopentadienyl and an indenyl group.
 11. Themethod of claim 7, wherein: a 1 mg/mL solution of the treated solidmetallocene compound in toluene has a moisture content of less than 5ppmw; a color of a 1 mg/mL solution of the treated solid metallocenecompound in toluene is unchanged for a time period of 36 hours at 25°C.; and a catalyst activity of a 1 mg/mL solution of the treated solidmetallocene compound in toluene is at least 80% of the catalyst activityobtained by using a 1 mg/mL solution of a fresh solid metallocenecompound in toluene, after a time period of 24 hours at 25° C., underthe same catalyst preparation and polymerization conditions.
 12. Themethod of claim 1, wherein: the treated solid metallocene compoundcomprises titanium, zirconium, hafnium, or a combination thereof; andthe method does not comprise a recrystallization step.
 13. The method ofclaim 12, wherein: subjecting the exposed solid metallocene compound toa sub-atmospheric pressure comprises a pressure of less than 10 torr;and a 1 mg/mL solution of the treated solid metallocene compound intoluene has a moisture content of less than 5 ppmw.
 14. The method ofclaim 1, wherein the treated solid metallocene compound comprises abridged zirconium or hafnium based metallocene compound with acyclopentadienyl group and a fluorenyl group.
 15. The method of claim14, wherein a catalyst activity of a 1 mg/mL solution of the treatedsolid metallocene compound in toluene is at least 80% of the catalystactivity obtained by using a 1 mg/mL solution of a fresh solidmetallocene compound in toluene, after a time period of 24 hours at 25°C., under the same catalyst preparation and polymerization conditions.16. The method of claim 1, wherein the treated solid metallocenecompound comprises an unbridged zirconium or hafnium based metallocenecompound containing two cyclopentadienyl groups, two indenyl groups, ora cyclopentadienyl and an indenyl group.
 17. The method of claim 16,wherein: the purging gas stream is a nitrogen gas stream comprising lessthan 10 ppmw of water and less than 10 ppmw of oxygen-containingcompounds; and a catalyst activity of a 1 mg/mL solution of the treatedsolid metallocene compound in toluene is at least 80% of the catalystactivity obtained by using a 1 mg/mL solution of a fresh solidmetallocene compound in toluene, after a time period of 24 hours at 25°C., under the same catalyst preparation and polymerization conditions.18. The method of claim 7, wherein: the method comprises fluidizing theexposed solid metallocene compound with the purging gas stream; and thetreated solid metallocene compound comprises titanium, zirconium,hafnium, or a combination thereof.
 19. The method of claim 7, wherein:the treated solid metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with a cyclopentadienyl group and afluorenyl group; and a catalyst activity of a 1 mg/mL solution of thetreated solid metallocene compound in toluene is at least 85% of thecatalyst activity obtained by using a 1 mg/mL solution of a fresh solidmetallocene compound in toluene, after a time period of 24 hours at 25°C., under the same catalyst preparation and polymerization conditions.20. The method of claim 7, wherein the purging gas stream is a nitrogengas stream comprising less than 10 ppmw of water and less than 10 ppmwof oxygen-containing compounds.